Tissue Flashcards
exam 1
what 3 things is classification of tissue based on?
- structure of cells
- composition of extracellular matrix
- cell function
epithelial tissue (structure, EC matrix, function)
one or more layers of closely packed cells, little to no EC matrix. Covers body surfaces, lines body/organ cavities, forms glands.
6 characteristics of epithelial tissue
- cellularity (tightly packed)
- distinct cell surfaces
- attached to basement membrane
- avascular
- innervation (high nerve supply)
- high regeneration capacity
3 distinct surfaces of epithelial tissue
- free (apical)
- lateral
- basal
free (apical) surface
in epithelial tissue, not attached to other cells, exposed either to the external environment or some internal body space
basement membrane
specialized type of EC material secreted by epithelial and connective tissues, strengthens attachment and forms a barrier between epithelium and underlying connective tissue
lateral surface
in epithelial tissue, attached to other epithelial cells
basal surface
in epithelial tissue, attached to the basement membrane
basement membrane layers
basal lamina
reticular lamina
how is epithelial tissue classified?
number of cell layers
shape of cells at apical surface
Functions of epithelial tissue
(no one structure in the body does all)
1. protect underlying structures (from dehydration, abrasion, destruction)
- selective permeability
- secreting substances
- sensation
simple epithelium
single layer of cells extending from basement membrane to free surface, typically in areas with minimum stress
stratified epithelium
more than one layer, but only the deepest layer attaches to the basement membrane, found in areas subject to stress
pseudostratified epithelium
type of simple epithelium that appears stratified due to nuclei in different locations
squamous epithelial tissue
cells are flat or scale like
transitional epithelial tissue
cells change shape as the organs stretch to a larger size and then collapse back to original shape, cuboidal to squamous
columnar epithelial tissue
cells are taller than they are wide